South Africa's case isn't the only one out there to try and stop the genocide in Palestine. There is also Defence for Children In'tl v Biden, 3:23-cv-5829.
But this isn't at all a difficult case Judge White.
The U.S. is a signatory to the 1948 Convention on the Prevention and Punishment of the Crime of Genocide. Congress passed the Genocide Convention Implementation Act (18 U.S.C. § 1091) in 1988, making it federal law. International law imposes on Biden and other high-level officials a legal duty to prevent genocide if there is a suspicion that it is occurring.
You have the persuasive authority of the International Court of Justice that ruled fairly unanimously that there was a possible genocide being perpetrated by Israel. See the 26 January 2024 order: https://icj-cij.org/sites/default/files/case-related/192/192-20240126-ord-01-00-en.pdf
Thus the Genocide Convention has been triggered.
The United States has significant capacity to influence Israel's actions as its primary provider of military and political support. Therefore, the U.S. has been obligated, since learning of the serious risk of genocide in Gaza, to exercise its considerable influence on the Israeli government to prevent the crime.